How to do ping reply.options ipv4 vs. ipv6?

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C#

C#4.0

Hi!
My research for a ping-solution for my software lead me to msdn and i got the solution at the end of my article. All works fine except a ping between two win7/ipv6-machines: The reply.Options-object is empty(null)!
Does anybody know why?
How do i get the reply.Options?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.NetworkInformation;
 
namespace TestPing
{
  class Program
  {
  // args[0] can be an IPaddress or host name.
  public static void Main(string[] args)
  {
    Ping pingSender = new Ping();
    PingOptions options = new PingOptions();
    // Use the default Ttl value which is 128,
    // but change the fragmentation behavior.
    options.DontFragment = true;
 
    // Create a buffer of 32 bytes of data to be transmitted.
    string data = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
    byte[] buffer = Encoding.ASCII.GetBytes(data);
    int timeout = 120;
    try
    {
    PingReply reply = pingSender.Send(args[0], timeout, buffer, options);
    Console.WriteLine("reply.Status {0} {1}", args[0], reply.Status.ToString());
    if (reply.Status == IPStatus.Success)
    {
      Console.WriteLine("Address: {0}", reply.Address.ToString());
      Console.WriteLine("RoundTrip time: {0}", reply.RoundtripTime);
   if (reply.Options != null) // reply.Status==Success but reply.Options is empty
            // for a ping from ipv6-adress to ipv6-adresses
      {
      Console.WriteLine("reply.Options:");
      Console.WriteLine("Time to live: {0}", reply.Options.Ttl);
      Console.WriteLine("Don't fragment: {0}", reply.Options.DontFragment);
      }
      Console.WriteLine("Buffer size: {0}", reply.Buffer.Length);
    }
    }
    catch(Exception ex)
    {
    Console.WriteLine("Exception {0}", ex.InnerException.Message);
    }
  }
 
 
  }
}